Monomer and polymerization process

ABSTRACT

The β-hydroxy carbamate, ethylenically unsaturated monomer of the invention can be polymerized as a homopolymer or copolymerized with other monomers. The polymerization can be carried out in an aqueous medium. The β-hydroxy carbamate monomer is polymerized to form water-soluble homopolymers or, if polymerized as a mixture with one or more comonomers, copolymers that are soluble, emulsifiable, or dispersible in water. The β-hydroxy carbamate monomer can be used as a replacement monomer for acrylamide.

This is a divisional of application Ser. No. 09/316,591, filed May 21,1999 now U.S. Pat. No. 6,346,591.

FIELD OF THE INVENTION

The invention concerns water-soluble and water-dispersible monomers andresins and processes for preparing aqueous resin compositions.

BACKGROUND OF THE INVENTION

Aqueous resin compositions are widely used in many different fields,including coatings, inks, detergents, additives for plastics, watertreatment, papermaking, and oil field production and refining. Inparticular, polyacrylamide and copolymers of acrylamide have gainedprominence as nonionic or cationic polymers that are water soluble.Because of industrial hygiene considerations associated with use ofacrylamide monomer, a replacement for acrylamide has long been sought.Modifications such as N-substituted acrylamide monomers (e.g.,N-methylol acrylamide) have been proposed. Polymers produced with theacrylamide and modified acrylamide monomers, however, have othershortcomings that make them undesirable. For example, the only reactivefunctional group of acrylamide is the unsaturation, so the polymerizedacrylamide unit does not provide a site for crosslinking or furthermodification. Crosslinking or other modification of the acrylamide unitwould be useful to reduce water sensitivity of the homopolymer orcopolymer at an appropriate time.

Thus it would be desirable to provide a water soluble monomer that couldbe used in the place of acrylamide, would not have the industrialhygiene concerns associated with acrylamide, and could be modified whenit would be appropriate to reduce the water sensitivity of a polymerprepared from the water soluble monomer.

SUMMARY OF THE INVENTION

We have now invented a method of preparing improved aqueous resincompositions. The resins are prepared by employing a β-hydroxy carbamatemonomer. The β-hydroxy carbamate monomer is polymerized to formwater-soluble homopolymers or, if polymerized as a mixture with one ormore comonomers, copolymers that are soluble or dispersible in water.The β-hydroxy carbamate monomer of the invention can be used as areplacement for acrylamide, especially for preparing aqueous resincompositions. The β-hydroxy carbamate monomer offers an advantage ofproviding reactive sites for crosslinking or other reactions afterpolymerization.

When used in connection with the invention, the term “carbamate group”refers to a group having a structure

in which R¹ is H or alkyl. Preferably, R¹ is H or alkyl of from 1 toabout 4 carbon atoms, and more preferably R¹ is H.

When polymerized, the monomer of the invention provides two reactivesites, a hydroxyl group and a reactive carbamate group, for crosslinkingor other modification of the polymer.

DETAILED DESCRIPTION OF THE INVENTION

The β-hydroxy carbamate monomer has an ethylenically unsaturated groupand a β-hydroxy carbamate group. Preferably, there are from 1 to about 4carbons between the ethylenically unsaturated group and the β-hydroxycarbamate group. The β-hydroxy carbamate monomer of the invention can berepresented by a structure:

wherein either each R² is hydrogen or one R² is hydrogen and the otherR² is methyl; n is from 1 to about 4, preferably 1; and one of Y and Zis OH and the other of Y and Z is

wherein R¹ is H or alkyl. Preferably, R¹ is H or alkyl of from 1 toabout 4 carbon atoms, and more preferably R¹ is H. In a typicalsynthesis of the β-hydroxy carbamate monomer, the reaction kineticsproduces a product that is a mixture of the compound in which Y ishydroxyl and Z is the carbamate group and the compound in which Z is ahydroxyl and Y is the carbamate group.

Unlike acrylonitrile, the monomer of the present invention has reactionrates comparable to other acrylic monomers. The monomer can bepolymerized to form a homopolymer. The polymerization can be carried outin water or in an a mixture that includes water. The monomer of theinvention can also be copolymerized with other monomers, includingacrylic, methacrylic, vinylic and allylic monomers, again preferably inan aqueous medium. Particular examples of suitable comonomers include,without limitation, acrylic acid, methacrylic acid, crotonic acid,esters of these acids, maleic anhydride, styrene, alpha-methylstyrene,vinyl acetate, and so on. Other functional monomers may be copolymerizedalong with the β-hydroxy carbamate monomer, including, withoutlimitation, acid- and anhydride-functional monomers such as thosealready mentioned; hydroxyl-functional monomers such as hydroxyalkylacrylates and methacrylates, amino-functional acrylic monomers such ast-butylaminoethyl methacrylate and t-butylamino-ethylacrylate;epoxide-functional monomers such as glycidyl acrylate, glycidylmethacrylate, and allyl glycidyl ether; other carbamate-functionalmonomers, and so on.

One way of preparing the β-hydroxy carbamate monomer of the invention isby reacting a glycidyl-group containing polymerizable monomer first withcarbon dioxide to convert the oxirane group to a cyclic carbonate group,and then with ammonia or a primary amine to convert the cyclic carbonategroup to a β-hydroxy carbamate group. Examples of suitable oxiranegroup-containing polymerizable monomers include, without limitation,glycidyl acrylate, glycidyl methacrylate, glycidyl crotonate, and allylglycidyl ether. Oxirane groups can be converted to carbamate groups byfirst converting to a cyclic carbonate group by reaction with CO₂. Thiscan be done at any pressure from atmospheric up to supercritical CO₂pressures, but is preferably under elevated pressure (e.g., 60-150 psi).The temperature for this reaction is preferably 60-150° C. Usefulcatalysts include any that activate an oxirane ring, such as tertiaryamine or quaternary salts (e.g., tetramethyl ammonium bromide),combinations of complex organotin halides and alkyl phosphonium halides(e.g., (CH₃)₃SnI, Bu₄SnI, Bu₄PI, and (CH₃)₄PI), potassium salts (e.g.,K₂CO₃, KI) preferably in combination with crown ethers, tin octoate,calcium octoate, and the like.

The cyclic carbonate group is reacted with ammonia or a primary amine.The primary amine preferably has up to four carbons, e.g. methyl amine.Preferably, the cyclic carbonate is reacted with ammonia. The ammoniamay be aqueous ammonia (i.e., NH₄OH). The reaction ring-opens the cycliccarbonate to form a β-hydroxy carbamate monomer according to theinvention.

The β-hydroxy carbamate monomer is water soluble. In one embodiment ofthe invention, the β-hydroxy carbamate monomer is polymerized to form ahomopolymer. The homopolymer is water-soluble. The β-hydroxy carbamatemonomer may be polymerized in the presence of free-radical initiators orwith a redox initiator system. Useful initiators and redox initiatorsystems are well-known. The polymerization may be carried out withoutsolvent or in an organic or aqueous medium. In a preferred embodiment,the β-hydroxy carbamate monomer is polymerized in an aqueous medium,preferably without any organic solvent or with a minor amount (up toabout 10% by weight of the aqueous medium) of a polar solvent such asmethanol, tetrahydrofuran, propylene glycol monomethyl ether, or otherwater-soluble or water-miscible solvents. The β-hydroxy carbamatemonomer may be dissolved in water along with the initiating system andpolymerized at a suitable temperature for the initiating system.

Alternatively, the β-hydroxy carbamate monomer may be polymerized as amixture with one or more comonomers. Depending on the comonomers chosen,and the ratio of the β-hydroxy carbamate monomer with the othercomonomers, the copolymers may be water soluble or water dispersible. Asused herein, “dispersible” or “water dispersible” encompasses not onlydispersible (solid) copolymers, but also emulsifiable or wateremulsifiable copolymers, that is, copolymers that are liquids or abovetheir T_(g) at room temperatures and thus form emulsions. Examples ofsuitable comonomers include, without limitation, α,β-ethylenicallyunsaturated monocarboxylic acids containing 3 to 5 carbon atoms such asacrylic, methacrylic, and crotonic acids and the esters of those acids;α,β-ethylenically unsaturated dicarboxylic acids containing 4 to 6carbon atoms and the anhydrides, monoesters, and diesters of thoseacids; vinyl esters, vinyl ethers, vinyl ketones, and aromatic orheterocyclic aliphatic vinyl compounds. Representative examples ofsuitable esters of acrylic, methacrylic, and crotonic acids include,without limitation, those esters from reaction with saturated aliphaticand cycloaliphatic alcohols containing 1 to 20 carbon atoms, such asmethyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl,2-ethylhexyl, lauryl, stearyl, cyclohexyl, trimethylcyclohexyl,tetrahydrofurfuryl, stearyl, sulfoethyl, and isobornyl acrylates,methacrylates, and crotonates; and polyalkylene glycol acrylates andmethacrylates. Representative examples of other ethylenicallyunsaturated polymerizable monomers include, without limitation, suchcompounds as fumaric, maleic, and itaconic anhydrides, monoesters, anddiesters with alcohols such as methanol, ethanol, propanol, isopropanol,butanol, isobutanol, and tert-butanol. Representative examples ofpolymerization vinyl monomers include, without limitation, suchcompounds as vinyl acetate, vinyl propionate, vinyl ethers such as vinylethyl ether, vinyl and vinylidene halides, and vinyl ethyl ketone.Representative examples of aromatic or heterocyclic aliphatic vinylcompounds include, without limitation, such compounds as styrene,α-methyl styrene, vinyl toluene, tert-butyl styrene, and 2-vinylpyrrolidone. The comonomers may be used in any combination.

Aqueous solutions including the β-hydroxy carbamate monomer may bepolymerized in the presence of a free radical initiator at moderatetemperatures, for example at temperature between about 20 and about 90°C. When a copolymer is emulsion polymerized, the β-hydroxy carbamatemonomer is preferably used in an amount sufficient to stabilize themonomer emulsion during the polymerization process. Typically, themonomers may include from about 2 to 100 percent by weight, preferablyfrom about 5 to 100 percent by weight, and more preferably from about 20to 100 percent by weight, of the β-hydroxy carbamate monomer.

Suitable free radical initiators include, without limitation, peroxide,persulfates, redox couples, azo compounds, and nonchemical meansincluding ultrasound, UV light, ionizing radiation, and so on. Chaintransfer agents may be included. Specific examples of useful initiatorsinclude, without limitation, hydrogen peroxide, ammonium persulfate, andredox systems, for example the combination of reducing species such asSO₃ ⁻ with oxidants such as Fe⁺³ or the oxidation of thiourea byoxidants such as Fe⁺³. Specific examples of chain transfer agentsinclude isopropanol, thiols such as octanethiol or mercaptoethanol,organohalides such as chloroform, diacetone alcohol, and the dimer ofα-methyl styrene.

The β-hydroxy carbamate monomer can also be polymerized by other methodssuitable for ethylenically unsaturated monomers. For example, withoutlimitation, the β-hydroxy carbamate monomer can be polymerized in anorganic solvent, particularly a water miscible solvent. The homopolymeror copolymer of the β-hydroxy carbamate monomer may then be diluted withwater or inverted into water with or without distillation or strippingof the organic solvent. Methods for inversion of a water-soluble orwater-dispersible polymer from an organic medium into an aqueous mediumare known.

In an alternative embodiment, the homopolymer or copolymer includingβ-hydroxy carbamate units may be prepared by including the correspondingcyclic carbonate monomer and forming the carbamate group from thecarbonate group at some time during the polymerization of thecorresponding cyclic carbonate monomer. For example, a primary amine orammonia can be charged to the polymerization reactor and react with thecyclic carbonate group during the polymerization. The reactor can bepressurized for ammonia or a gaseous primary amine. The ammonia orprimary amine could also be added during the polymerization reaction.

The homopolymers and copolymers of the β-hydroxy carbamate monomer mayhave weight average molecular weights of from about 5000 to over amillion. The most desirable weight average molecular weight will dependupon the use intended for the polymer. When the β-hydroxy carbamatemonomer is used as a replacement for acrylamide for a particularapplication, the amount of the β-hydroxy carbamate monomer included andthe preferred weight average molecular weight of the polymer preparedfrom it is comparable to the corresponding values for an acrylamidepolymer for that application.

Homopolymers and copolymers of the β-hydroxy carbamate monomer may beused in coating compositions, particularly waterborne coatingcompositions including topcoats. The homopolymers and copolymers of theβ-hydroxy carbamate monomer may also be used in other applications,especially in applications where acrylamide polymers have been used,including, without limitation, leather treatment, textile treatments,crop protection uses such as seed coatings, and in manufacture of fibersand inks. A homopolymer of the β-hydroxy carbamate monomer may also beused as a dispersant or emulsifier for another polymer in preparing anaqueous composition. In particular, homopolymers or copolymers of theβ-hydroxy carbamate monomer may be used to incorporate hydrophobicresins and polymers into aqueous compositions. For example, theβ-hydroxy carbamate monomer may be used in the methods disclosed inGrandhee, U.S. Pat. Nos. 5,569,715 and 5,786,420 and Martin et al., U.S.Pat. No. 5,071,904, all three patents being incorporated herein byreference.

In one embodiment of the invention, the β-hydroxy carbamate monomer iscopolymerized with at least one monomer capable of forming a cationicgroup in water when salted. Examples of such cation-forming monomersinclude those having an aromatic group, preferably a quaternary ammoniumsalt obtained by the reaction of benzyl chloride and with an aminomonomer such as dimethylaminoethyl (meth)acrylate,diethylaminoethyl(meth)acrylate, and dimethylaminohydroxylpropyl(meth)acrylate. The cationic copolymer is useful in water treatment,papermaking, oil field production and refining applications.

In another preferred embodiment, the homopolymers and copolymers of theβ-hydroxy carbamate monomer is used to prepare a coating composition.The coating composition preferably further includes a curing agent orcrosslinker that is reactive with the one or both of the hydroxyl andcarbamate functionalities of the β-hydroxy carbamate monomer. The curingagent has, on average, at least about two reactive functional groups.The functional groups may be of more than one kind, each kind beingreactive with one or both of the hydroxyl and carbamate groups.

Useful curing agents include materials having active methylol ormethylalkoxy groups, such as aminoplast crosslinking agents orphenol/formaldehyde adducts; curing agents that have isocyanate groups,particularly blocked isocyanate curing agents, curing agents that haveepoxide groups, amine groups, acid groups, siloxane groups, cycliccarbonate groups, and anhydride groups; and mixtures thereof. Examplesof preferred curing agent compounds include, without limitation,melamine formaldehyde resin (including monomeric or polymeric melamineresin and partially or fully alkylated melamine resin), blocked orunblocked polyisocyanates (e.g., toluene diisocyanate, MDI, isophoronediisocyanate, hexamethylene diisocyanate, biurets, allophanates, andisocyanurates of these, which may be blocked for example with, e.g.,alcohols, pyrazole compounds, or oximes), urea resins (e.g., methylolureas such as urea formaldehyde resin, alkoxy ureas such as butylatedurea formaldehyde resin), polyanhydrides (e.g., polysuccinic anhydride),and polysiloxanes (e.g., trimethoxy siloxane). Another suitablecrosslinking agent is tris(alkoxy carbonylamino) triazine (availablefrom Cytec Industries under the tradename TACT). The curing agent may becombinations of these, particularly combinations that include aminoplastcrosslinking agents. Aminoplast resins such as melamine formaldehyderesins or urea formaldehyde resins are especially preferred.Combinations of tris(alkoxy carbonylamino) triazine with a melamineformaldehyde resin and/or a blocked isocyanate curing agent are likewisesuitable and desirable. Component (b) may also contain groups that arereactive with the carbamate group of component (a), such as an acrylicpolymer containing polymerized isobutoxymethyl acrylamide groups.

When monomers having a reactive group other than carbamate or hydroxylare included in the copolymer, a crosslinker suitable for that reactivegroup may be included in the composition.

Although aqueous coating compositions that are free of regulatedvolatile organic compounds are preferred, a solvent may optionally beutilized in the coating composition used in the practice of the presentinvention. In general, the solvent can be any organic solvent and/orwater. In one preferred embodiment, the solvent is a polar organicsolvent. More preferably, the solvent is selected from polar aliphaticsolvents or polar aromatic solvents. Still more preferably, the solventis a ketone, ester, acetate, aprotic amide, aprotic sulfoxide, aproticamine, or a combination of any of these. Examples of useful solventsinclude, without limitation, methyl ethyl ketone, methyl isobutylketone, m-amyl acetate, ethylene glycol butyl ether-acetate, propyleneglycol monomethyl ether acetate, xylene, N-methylpyrrolidone, blends ofaromatic hydrocarbons, and mixtures of these. In another preferredembodiment, the solvent is water or a mixture of water with smallamounts of co-solvents.

The coating composition used in the practice of the invention mayinclude a catalyst to enhance the cure reaction. For example, whenaminoplast compounds, especially monomeric melamines, are used as acuring agent, a strong acid catalyst may be utilized to enhance the curereaction. Such catalysts are well-known in the art and include, withoutlimitation, p-toluene sulfonic acid, dinonylnaphthalene disulfonic acid,dodecylbenzenesulfonic acid, phenyl acid phosphate, monobutyl maleate,butyl phosphate, and hydroxy phosphate ester. Strong acid catalysts areoften blocked, e.g. with an amine. Other catalysts that may be useful inthe composition of the invention include Lewis acids, zinc salts, andtin salts.

In a preferred embodiment of the invention, the organic solvent ispresent in the coating composition in an amount of from 0 weight percentto about 99 weight percent, preferably from 0 weight percent to about 70weight percent, and more preferably from about 1 weight percent to about20 weight percent. In a more preferred embodiment, the coatingcomposition is aqueous and includes water in an amount of from about0.01 weight percent to about 99 weight percent, preferably from about 5weight percent to about 80 weight percent, and more preferably fromabout 20 weight percent to about 70 weight percent.

Coating compositions can be coated on the article by any of a number oftechniques well-known in the art. These include, for example, spraycoating, dip coating, roll coating, curtain coating, and the like. Forautomotive body panels, spray coating is preferred.

The coating compositions of the invention include electrocoat primercompositions, primer surfacer compositions, and topcoat compositions,including one-layer pigmented topcoat compositions as well as either orboth of the clearcoat and basecoat layers of a two-layer topcoatcompositions. When the resins of the invention are utilized in aqueouscompositions, they may include monomers with groups that can be salted,i.e., acid groups or amine groups. In the case of electrocoat primercompositions, an acid group or amine group is used to deposit the resinon the anode or cathode.

Additional agents, for example surfactants, fillers, stabilizers,wetting agents, dispersing agents, adhesion promoters, UV absorbers,hindered amine light stabilizers, etc. may be incorporated into thecoating composition. While such additives are well-known in the priorart, the amount used must be controlled to avoid adversely affecting thecoating characteristics. The coating composition according to theinvention is preferably utilized in a high-gloss coating and/or as theclearcoat of a composite color-plus-clear coating. High-gloss coatingsas used herein are coatings having a 20° gloss (ASTM D523-89) or a DOI(ASTM E430-91) of at least 80.

When the coating composition of the invention is used as a high-glosspigmented paint coating or as a basecoat of a basecoat-clearcoatcomposite coating, the pigment may be any organic or inorganic compoundsor colored materials, fillers, metallic or other inorganic flakematerials such as mica or aluminum flake, and other materials of kindthat the art normally includes in such coatings. Pigments and otherinsoluble particulate compounds such as fillers are usually used in thecomposition in an amount of 1% to 100%, based on the total solid weightof binder components (i.e., a pigment-to-binder ratio of 0.1 to 1).

When the coating composition according to the invention is used as theclearcoat or basecoat of a basecoat-clearcoat composite coating, thecomposition forming the other layer of the composite coating may any ofa number of types well-known in the art, and does not requireexplanation in detail herein. Polymers known in the art to be useful inclearcoat and basecoat compositions include acrylics, vinyls,polyurethanes, polycarbonates, polyesters, alkyds, and polysiloxanes.Preferred polymers include acrylics and polyurethanes. In one preferredembodiment of the invention, the basecoat composition also utilizes acarbamate-functional acrylic polymer. Basecoat polymers may bethermoplastic, but are preferably crosslinkable and comprise one or moretype of crosslinkable functional groups. Such groups include, forexample, hydroxy, isocyanate, amine, epoxy, acrylate, vinyl, silane, andacetoacetate groups. These groups may be masked or blocked in such a wayso that they are unblocked and available for the crosslinking reactionunder the desired curing conditions, generally elevated temperatures.Useful crosslinkable functional groups include hydroxy, epoxy, acid,anhydride, silane, and acetoacetate groups. Preferred crosslinkablefunctional groups include hydroxy functional groups and amino functionalgroups.

The coating compositions described herein are preferably subjected toconditions so as to cure the coating layers. Although various methods ofcuring may be used, heat-curing is preferred. Generally, heat curing iseffected by exposing the coated article to elevated temperaturesprovided primarily by radiative heat sources. Curing temperatures willvary depending on the particular blocking groups used in thecross-linking agents, however they generally range between 90° C. and180° C. The first compounds according to the present invention arepreferably reactive even at relatively low cure temperatures. Thus, in apreferred embodiment, the cure temperature is preferably between 115° C.and 150° C., and more preferably at temperatures between 115° C. and140° C. for a blocked acid catalyzed system. For an unblocked acidcatalyzed system, the cure temperature is preferably between 80° C. and100° C. The curing time will vary depending on the particular componentsused, and physical parameters such as the thickness of the layers,however, typical curing times range from 15 to 60 minutes, andpreferably 15-25 minutes for blocked acid catalyzed systems and 10-20minutes for unblocked acid catalyzed systems.

The invention is further described in the following example. The exampleis merely illustrative and does not in any way limit the scope of theinvention as described and claimed. All parts are parts by weight unlessotherwise noted.

EXAMPLE 1 Preparation of β-Hydroxy Carbamate Propyl Methacrylate

A methanolic solution of the cyclic carbonate of glycidyl methacrylate(available from Dow Corp., Midland, Mich.) was prepared by dissolving1095.4 grams of the cyclic carbonate of glycidyl methacrylate in 1140grams of methanol. The dissolved monomer was reacted with anhydrousammonia, which was bubbled into the solution over a period of about 2.75hr. The initial temperature was about 17° C., and the exotherm peaked atabout 30° C. and was controlled by holding the reactor in a coolingbath. After the ammonia add was ended, the reactor was closed. Thecontents of the flask were stirred for an additional 5 hrs. Wheninfrared analysis showed no remaining carbonate, 0.1 gram of MEHQ wasadded to stabilize the monomer and the methanol and unreacted ammoniaare distilled under vacuum to yield a solid product having a slight pinkcolor from the MEHQ.

The solid product (1147 g) is dissolved in 751.8 grams of water to yielda 60.4% nonvolatile solution.

EXAMPLE 2 Preparation of a Homopolymer of β-Hydroxy Carbamate PropylMethacrylate

A reactor was charged with 193.4 grams of deionized water and heated to80° F. under a nitrogen atmosphere. After the water had reached 80° C.,a mixture of 306.2 grams of the solution of Example 1 and 11.2 grams ofammonium persulfate was added over a period of one hour. A solution of0.9 grams of ammonium persulfate in 10 grams of deionized water wasadded over about 15 minutes. The reaction mixture was held for about 45minutes longer, then cooled. The product was an aqueous polymer solutionthat had a faint haze.

EXAMPLE 3 Preparation of a Coating Composition Containing theHomopolymer of β-Hydroxy Carbamate Propyl Methacrylate

A coating composition was prepared by combining 21.3 grams of theaqueous homopolymer solution of Example 2 with 6.1 grams ofhexamethoxymethylated melamine and 0.2 gram of an acid catalyst (70%solution of dodecylbenzene sulfonic acid). The mixture was drawn down 7mm thick over a steel panel primed with electrocoat primer. The drawndown coating layer was allowed to flash to 10 minutes at 180° F. to aidin evaporation of the water. The coating layer was baked for 30 minutesat 285° F. The resulting cured film was hard and passed solventresistance tests of 200 double rubs with methyl ethyl ketone and aone-minute soak in methyl ethyl ketone.

The coating composition of Example 3 was examined for 7 mil drawdownscured at 285° F. for 30 minutes on the substrates shown in the tablebelow.

Parts of homopolymer (NV) 12.9 12.9 Parts of Resimene 747 6.1 6.1 (fromSolutia) Parts of dodecylbenzene 0.14 0.14 sulfonic acid SubstrateElectrocoat Steel panel primed panel 200 MEK double rubs pass pass 1minute MEK no effect no effect Soak

EXAMPLE 4 Preparation of β-Hydroxy Carbamate Propyl Methacrylate

A mixture of 200 parts by weight of the cyclic carbonate of glycidylmethacrylate in 50.7 parts by weight of deionized water was charged to areaction vessel and 59.6 parts by weight of concentrated ammoniumhydroxide (28 to 32% ammonia) were slowly added. The two phase systemslowly converted into one phase as the carbonate monomer reacted to formthe β-hydroxy carbamate propyl methacrylate product.

EXAMPLE 5 Preparation of Emulsion of a Copolymer of β-Hydroxy CarbamatePropyl Methacrylate

The following materials were homogenized in two passes at 8000 PSI usinga Microfluidizer® (Microfluidics Corporation) to form a homogenizedmonomer mixture using the techniques described in U.S. Pat. Nos.5,786,420 and 5,569,715: 1062 parts by weight of a polyurethane polymer(80% NV by weight the reaction product of 1507 parts by weight of apolyester (theoretical OH equivalent weight of 748), 158 parts by weightof neopentyl glycol, 83 parts by weight of trimethylolpropane monoallylether, 1012 parts by weight of tetramethyl-m-xylene diisocyanate, and288 parts by weight of trimethylolpropane), 747 parts by weight ofmethyl methacrylate, 356 parts by weight of butyl acrylate, 118 parts byweight of 2-hydroxyethyl methacrylate, 237 parts by weight of butylmethacrylate, 2010 parts by weight of deionized water, and 264 parts byweight of ABEX EP 110 (available from Rhodia Corp.).

In a suitable reactor, 360 parts by weight of deionized water was heatedunder an inert atmosphere to 82° C. A total of 756 parts by weight ofthe homogenized monomer mixture and a solution of 0.81 parts by weightof ammonium persulfate in 45 parts by weight of deionized water wereadded concurrently over 1.5 hours.

When both additions were complete, a mixture of 135 parts by weight ofmethyl methacrylate, 101 parts by weight of butyl acrylate, 75 parts byweight of the aqueous β-hydroxy carbamate propyl methacrylate solutionof Example 4, 56 parts by weight of butyl methacrylate, 11.8 parts byweight of methacrylic acid, and 1.5 parts by weight of Igepal CO-850(from Rhodia) was added over two hours. The reaction mixture was thenheld for two hours at 82° C. The final product had a measurednonvolatile by weight of 46.3% and a particle size of 215 nm.

EXAMPLE 6 Preparation of Emulsion of a Copolymer of β-Hydroxy CarbamatePropyl Methacrylate

This example is similar to Example 5, but does not include the2-hydroxyethyl methacrylate monomer in the polymerization.

The following materials were homogenized in two passes at 8000 PSI usinga Microfluidizer® (Microfluidics Corporation) to form a homogenizedmonomer mixture using the techniques described in U.S. Pat. Nos.5,786,420 and 5,569,715: 176 parts by weight of the polyurethane polymerdescribed in Example 5, 86 parts by weight of methyl methacrylate, 64parts by weight of butyl acrylate, 43 parts by weight of butylmethacrylate, 48 parts by weight of the aqueous β-hydroxy carbamatepropyl methacrylate solution of Example 4, 364 parts by weight deionizedwater, and 48 parts by weight of ABEX EP 110.

In a suitable reactor, 365 parts by weight of deionized water was heatedunder an inert atmosphere to 82° C. A total of 770 parts by weight ofthe homogenized monomer mixture and a mixture of 44 parts by weight ofdeionized water and 0.81 parts by weight of ammonium persulfate wereadded concurrently over 1.5 hours.

When both additions were complete, a mixture of 145 parts by weight ofmethyl methacrylate, 100 parts by weight of butyl acrylate, 74 parts byweight of the aqueous β-hydroxy carbamate propyl methacrylate solutionof Example 4, 55 parts by weight of butyl methacrylate, and 1.5 parts byweight of Igepal CO-850 (from Rhodia) was added over two hours. Thereaction mixture was then held for two hours at 82° C. The final producthad a measured nonvolatile by weight of 44% and a particle size of 181nm.

Comparative Example A

The following materials were homogenized in two passes at 8000 PSI usinga Microfluidizer® (Microfluidics Corporation) to form a homogenizedmonomer mixture using the techniques described in U.S. Pat. Nos.5,786,420 and 5,569,715: 1062 parts by weight of the polyurethanepolymer described in Example 5, 107 parts by weight of methylmethacrylate, 64 parts by weight of butyl acrylate, 43 parts by weightof butyl methacrylate, 363.1 parts by weight of deionized water, and 48parts by weight of ABEX EP 110.

In a suitable reactor, 369 parts by weight of deionized water was heatedunder an inert atmosphere to 82° C. A total of 774 parts by weight ofthe homogenized monomer mixture and a solution of 0.83 parts by weightof ammonium persulfate in 46 parts by weight of deionized water wereadded concurrently over 1.5 hours.

When both additions were complete, a mixture of 173 parts by weight ofmethyl methacrylate, 104 parts by weight of butyl acrylate, 57 parts byweight of butyl methacrylate, and 1.5 parts by weight of Igepal CO-850was added over two hours. The reaction mixture was then held for twohours at 82° C. The final product had a measured nonvolatile by weightof 45.4% and a particle size of 220 nm.

Curable Compositions

The emulsion copolymers of Example 5, Example 6, and Comparative ExampleA were formulated into thermosetting compositions and tested for curingproperties. The cure profiles were established using 8 mil drawdowns onglass slides, and curing at 285° F. for 30 minutes. The systems wereevaluated for cure using 200 double rubs with methyl ethyl ketone.

Parts by weight Results of 200 Parts Parts by weight dodecylbenzene MEKdouble by weight Resin Resimene 747¹ sulfonic acid rubs 100 partsExample 5 1.28 0.09 Pass 100 parts Example 5 1.28 0.00 Pass 100 partsExample 5 0.00 0.00 Failed 100 parts Example 6 1.28 0.00 Pass 100 partsComp. 1.28 0.00 Failed Ex. A ^(1.)available from Solutia

The results in the above table demonstrate that the monomer of theinvention provides groups available for crosslinking in thermosettingcompositions.

The invention has been described in detail with reference to preferredembodiments thereof. It should be understood, however, that variationsand modifications can be made within the spirit and scope of theinvention and of the following claims.

What is claimed is:
 1. A homopolymer having a repeating structure

wherein either each R² is hydrogen or one R² is hydrogen and the otherR² is methyl; n is from 1 to about 4; and one of Y and Z is OH and theother of Y and Z is

wherein R¹ is H or alkyl.
 2. A homopolymer according to claim 1, whereinR¹ is H.
 3. A composition comprising a homopolymer according to claim 1.4. A composition according to claim 3, further comprising water.
 5. Acomposition according to claim 3, further comprising an organic solvent.6. A composition according to claim 5, wherein the organic solvent iswater miscible.
 7. A copolymer prepared by addition polymerization of acompound having a structure

wherein either each R² is hydrogen or one R² is hydrogen and the otherR² is methyl, n is from 1 to about 4, and one of Y and Z is OH and theother of Y and Z is

wherein R¹ is H or alkyl, with at least one further additionpolymerizable compound.
 8. A copolymer according to claim 7, wherein thefurther addition polymerizable compound or compounds are selected fromthe group consisting of acrylic acid, methacrylic acid, esters ofacrylic acid, esters of methacrylic acid, α, β-ethylenically unsaturateddicarboxylic acids containing 4 to 6 carbon atoms and esters thereof,aromatic vinyl compounds, heterocyclic aliphatic vinyl compounds, andcombinations thereof.
 9. A composition comprising a copolymer accordingto claim
 7. 10. A composition according to claim 9, further comprisingwater.
 11. A composition according to claim 9, further comprising anorganic solvent.
 12. A composition according to claim 11, wherein theorganic solvent is water miscible.